diff --git a/sanguo_trader/models.py b/sanguo_trader/models.py
new file mode 100644
index 0000000..93cf6db
--- /dev/null
+++ b/sanguo_trader/models.py
@@ -0,0 +1,80 @@
+"""模拟盘数据模型（immutable DTOs）。
+
+数据类承载配置与订单/成交/拒单状态，跨模块传递时保持不可变。
+费率默认值见 §6.4（Issue #3 费率参数化）。
+"""
+from dataclasses import dataclass
+from enum import Enum
+
+
+class MatchSession(str, Enum):
+    """撮合时点（spec §6.1）。
+
+    - NEXT_OPEN：下一根 bar 的 open（收盘型策略，安全）
+    - CURRENT_CLOSE：当根 bar 的 close（尾盘抓涨停型，策略不得用当根 OHLC）
+    - CALL_AUCTION：集合竞价（首版预留）
+    """
+
+    NEXT_OPEN = "next_open"
+    CURRENT_CLOSE = "current_close"
+    CALL_AUCTION = "call_auction"
+
+
+class OrderSide(str, Enum):
+    BUY = "buy"
+    SELL = "sell"
+
+
+@dataclass(frozen=True)
+class AccountConfig:
+    """账户费率/撮合参数（Issue #3 全字段可配）。"""
+
+    initial_capital: float
+    rate: float = 0.0003              # 佣金率
+    min_commission: float = 5.0       # 最低佣金 5 元
+    stamp_duty_rate: float = 0.0005   # 印花税（仅卖，2023.8.28 起 0.05%）
+    transfer_fee_rate: float = 0.00001  # 过户费率（沪深双向 ×2，由 Account 计算）
+    slippage: float = 0.0
+    pricetick: float = 0.01
+    size: float = 1.0
+
+
+@dataclass(frozen=True)
+class PaperOrder:
+    """策略下单请求。match_session 决定撮合时点。"""
+
+    strategy_id: str
+    symbol: str
+    side: OrderSide
+    price: float
+    volume: int
+    is_market: bool = True
+    match_session: MatchSession = MatchSession.NEXT_OPEN
+
+
+@dataclass(frozen=True)
+class PaperTrade:
+    """已成交记录（含费用拆分）。transfer_fee 为单边，Account 扣款时 ×2。"""
+
+    strategy_id: str
+    symbol: str
+    side: OrderSide
+    price: float
+    volume: int
+    commission: float
+    stamp_duty: float
+    transfer_fee: float
+    bar_date: str
+    match_session: MatchSession
+
+
+@dataclass(frozen=True)
+class PaperReject:
+    """拒单记录。reason 枚举：limit_up_locked / limit_down_locked /
+    limit_not_touched / volume_below_min_lot / unsupported_match_session /
+    insufficient_cash / blocked_by_strategy=<id>。"""
+
+    strategy_id: str
+    symbol: str
+    reason: str
+    bar_date: str
diff --git a/tests/trader/__init__.py b/tests/trader/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/trader/test_models.py b/tests/trader/test_models.py
new file mode 100644
index 0000000..84f6f14
--- /dev/null
+++ b/tests/trader/test_models.py
@@ -0,0 +1,89 @@
+"""PaperAccount/Order/Trade/Reject 数据类测试。"""
+from sanguo_trader.models import (
+    AccountConfig,
+    PaperOrder,
+    PaperTrade,
+    PaperReject,
+    MatchSession,
+    OrderSide,
+)
+
+
+def test_account_config_defaults():
+    cfg = AccountConfig(initial_capital=1_000_000)
+    assert cfg.initial_capital == 1_000_000
+    assert cfg.rate == 0.0003
+    assert cfg.min_commission == 5.0
+    assert cfg.stamp_duty_rate == 0.0005
+    assert cfg.transfer_fee_rate == 0.00001
+    assert cfg.slippage == 0
+    assert cfg.pricetick == 0.01
+
+
+def test_account_config_is_frozen():
+    import dataclasses
+
+    cfg = AccountConfig(initial_capital=1_000_000)
+    assert dataclasses.is_dataclass(cfg)
+    # frozen=True → 不可变
+    try:
+        cfg.rate = 0.001  # type: ignore[misc]
+    except dataclasses.FrozenInstanceError:
+        pass
+    else:
+        raise AssertionError("AccountConfig 应为 frozen dataclass")
+
+
+def test_paper_order_defaults_next_open():
+    o = PaperOrder(
+        strategy_id="s1",
+        symbol="600000",
+        side=OrderSide.BUY,
+        price=10.0,
+        volume=100,
+        is_market=True,
+    )
+    assert o.match_session == MatchSession.NEXT_OPEN
+
+
+def test_paper_order_explicit_current_close():
+    o = PaperOrder(
+        strategy_id="s1",
+        symbol="600000",
+        side=OrderSide.SELL,
+        price=10.0,
+        volume=100,
+        is_market=False,
+        match_session=MatchSession.CURRENT_CLOSE,
+    )
+    assert o.match_session == MatchSession.CURRENT_CLOSE
+    assert o.is_market is False
+
+
+def test_paper_trade_fields():
+    t = PaperTrade(
+        strategy_id="s1",
+        symbol="600000",
+        side=OrderSide.BUY,
+        price=10.0,
+        volume=100,
+        commission=5.0,
+        stamp_duty=0.0,
+        transfer_fee=0.01,
+        bar_date="2024-01-02",
+        match_session=MatchSession.NEXT_OPEN,
+    )
+    assert t.volume == 100
+    assert t.commission == 5.0
+    assert t.bar_date == "2024-01-02"
+
+
+def test_paperReject_records_reason():
+    r = PaperReject(
+        strategy_id="s1",
+        symbol="600000",
+        reason="limit_up_locked",
+        bar_date="2024-01-02",
+    )
+    assert r.reason == "limit_up_locked"
+    assert r.symbol == "600000"